1. Field of the Invention
The present invention relates to cosmetic and/or dermatological compositions intended to protect, nourish and/or firm the skin, both of the face and of the body, or even of the scalp. It relates more particularly to a composition comprising at least one active agent which is conveyed via at least two distinct types of lipid vesicles. The present invention also relates to a method for protecting, nourishing and/or firming the skin by the topical application of such a composition.
2. Discussion of the Background
The skin is subjected to daily aggression, especially atmospheric aggression, resulting in a drying and/or a depletion of fatty substances in the skin, requiring it to be regularly protected, nourished or even firmed up. Thus, numerous protective, nourishing and/or firming compositions are currently available on the market. Unfortunately, the effectiveness of these compositions is often insufficient, the latter providing only a partial treatment of the skin.
Moreover, many examples are known of cosmetic or dermatological compositions intended for treating the skin, which have one or more active agents that are suitable for treating the skin and which are encapsulated in lipid spherules or vesicles (also known as liposomes).
Lipid spherules or vesicles are understood to refer to particles formed of a membrane consisting of one or more concentric lamellae, these lamellae containing one or more bimolecular layers of amphiphilic lipids encapsulating an aqueous phase. The aqueous phase may contain water-soluble active substances and the bimolecular layers of amphiphilic lipids may contain lipophilic active substances.
These spherules generally have a mean diameter of between 10 nm and 5000 nm. Among the many documents published regarding this matter, there may be mentioned the French Certificate of Addition 2,408,387 which describes a composition based on aqueous dispersions of ionic or nonionic lipid spherules encapsulating at least one active substance. More precisely, this document describes compositions containing at least two dispersions of spherules containing different active agents, for the purpose of obtaining a mixed system, that is to say a system in which a first dispersion of spherules containing a first type of active substance is combined with a second dispersion of spherules containing another type of active substance, which enables the two types of substances to act simultaneously at the time of treatment and possibly to obtain a synergistic effect which would not be produced if these two categories of substances were made to act successively and separately.
It in well known that the skin consists of surface layers, the stratum corneum, and of deep layers, the live epidermis and the dermis. However, specific delivery of such an active agent into the surface layers and, simultaneously, of the same or another active agent into the deep layers, is not known from the prior art.
Thus, there remains a need for a method for protecting, nourishing, and/or firming the skin by simultaneously treating the surface layers and deep layers of the skin. There also remains a need for compositions useful in such methods.